/**
 *    @author zz85 / http://twitter.com/blurspline / http://www.lab4games.net/zz85/blog
 *
 *    A general perpose camera, for setting FOV, Lens Focal Length,
 *        and switching between perspective and orthographic views easily.
 *        Use this only if you do not wish to manage
 *        both a Orthographic and Perspective Camera
 *
 */

/* eslint-disable */
import * as THREE from 'three';

THREE.CombinedCamera = function ( width, height, fov, near, far, orthoNear, orthoFar ) {

    THREE.Camera.call( this );

    this.fov = fov;

    this.far = far;
    this.near = near;

    this.left = - width / 2;
    this.right = width / 2;
    this.top = height / 2;
    this.bottom = - height / 2;

    this.aspect =  width / height;
    this.zoom = 1;
    this.view = null;
    // We could also handle the projectionMatrix internally, but just wanted to test nested camera objects

    this.cameraO = new THREE.OrthographicCamera( width / - 2, width / 2, height / 2, height / - 2,     orthoNear, orthoFar );
    this.cameraP = new THREE.PerspectiveCamera( fov, width / height, near, far );

    this.toPerspective();

};

THREE.CombinedCamera.prototype = Object.create( THREE.Camera.prototype );
THREE.CombinedCamera.prototype.constructor = THREE.CombinedCamera;

THREE.CombinedCamera.prototype.toPerspective = function () {

    // Switches to the Perspective Camera

    this.near = this.cameraP.near;
    this.far = this.cameraP.far;

    this.cameraP.aspect = this.aspect;
    this.cameraP.fov =  this.fov / this.zoom ;
    this.cameraP.view = this.view;

    this.cameraP.updateProjectionMatrix();

    this.projectionMatrix = this.cameraP.projectionMatrix;

    this.inPerspectiveMode = true;
    this.inOrthographicMode = false;

};

THREE.CombinedCamera.prototype.toOrthographic = function () {

    // Switches to the Orthographic camera estimating viewport from Perspective

    var fov = this.fov;
    var aspect = this.cameraP.aspect;
    var near = this.cameraP.near;
    var far = this.cameraP.far;

    // The size that we set is the mid plane of the viewing frustum

    var hyperfocus = ( near + far ) / 2;

    var halfHeight = Math.tan( fov * Math.PI / 180 / 2 ) * hyperfocus;
    var halfWidth = halfHeight * aspect;

    halfHeight /= this.zoom;
    halfWidth /= this.zoom;

    this.cameraO.left = - halfWidth;
    this.cameraO.right = halfWidth;
    this.cameraO.top = halfHeight;
    this.cameraO.bottom = - halfHeight;
    this.cameraO.view = this.view;

    this.cameraO.updateProjectionMatrix();

    this.near = this.cameraO.near;
    this.far = this.cameraO.far;
    this.projectionMatrix = this.cameraO.projectionMatrix;

    this.inPerspectiveMode = false;
    this.inOrthographicMode = true;

};

THREE.CombinedCamera.prototype.copy = function ( source ) {

    THREE.Camera.prototype.copy.call( this, source );

    this.fov = source.fov;
    this.far = source.far;
    this.near = source.near;

    this.left = source.left;
    this.right = source.right;
    this.top = source.top;
    this.bottom = source.bottom;

    this.zoom = source.zoom;
    this.view = source.view === null ? null : Object.assign( {}, source.view );
    this.aspect = source.aspect;

    this.cameraO.copy( source.cameraO );
    this.cameraP.copy( source.cameraP );

    this.inOrthographicMode = source.inOrthographicMode;
    this.inPerspectiveMode = source.inPerspectiveMode;

    return this;

};

THREE.CombinedCamera.prototype.setViewOffset = function( fullWidth, fullHeight, x, y, width, height ) {

    this.view = {
        fullWidth: fullWidth,
        fullHeight: fullHeight,
        offsetX: x,
        offsetY: y,
        width: width,
        height: height
    };

    if ( this.inPerspectiveMode ) {

        this.aspect = fullWidth / fullHeight;

        this.toPerspective();

    } else {

        this.toOrthographic();

    }

};

THREE.CombinedCamera.prototype.clearViewOffset = function() {

    this.view = null;
    this.updateProjectionMatrix();

};

THREE.CombinedCamera.prototype.setSize = function( width, height ) {

    this.cameraP.aspect = width / height;
    this.left = - width / 2;
    this.right = width / 2;
    this.top = height / 2;
    this.bottom = - height / 2;

};


THREE.CombinedCamera.prototype.setFov = function( fov ) {

    this.fov = fov;

    if ( this.inPerspectiveMode ) {

        this.toPerspective();

    } else {

        this.toOrthographic();

    }

};

// For maintaining similar API with PerspectiveCamera

THREE.CombinedCamera.prototype.updateProjectionMatrix = function() {

    if ( this.inPerspectiveMode ) {

        this.toPerspective();

    } else {

        this.toPerspective();
        this.toOrthographic();

    }

};

/*
* Uses Focal Length (in mm) to estimate and set FOV
* 35mm (full frame) camera is used if frame size is not specified;
* Formula based on http://www.bobatkins.com/photography/technical/field_of_view.html
*/
THREE.CombinedCamera.prototype.setLens = function ( focalLength, filmGauge ) {

    if ( filmGauge === undefined ) filmGauge = 35;

    var vExtentSlope = 0.5 * filmGauge /
            ( focalLength * Math.max( this.cameraP.aspect, 1 ) );

    var fov = THREE.Math.RAD2DEG * 2 * Math.atan( vExtentSlope );

    this.setFov( fov );

    return fov;

};


THREE.CombinedCamera.prototype.setZoom = function( zoom ) {

    this.zoom = zoom;

    if ( this.inPerspectiveMode ) {

        this.toPerspective();

    } else {

        this.toOrthographic();

    }

};

THREE.CombinedCamera.prototype.toFrontView = function() {

    this.rotation.x = 0;
    this.rotation.y = 0;
    this.rotation.z = 0;

    // should we be modifing the matrix instead?

};

THREE.CombinedCamera.prototype.toBackView = function() {

    this.rotation.x = 0;
    this.rotation.y = Math.PI;
    this.rotation.z = 0;

};

THREE.CombinedCamera.prototype.toLeftView = function() {

    this.rotation.x = 0;
    this.rotation.y = - Math.PI / 2;
    this.rotation.z = 0;

};

THREE.CombinedCamera.prototype.toRightView = function() {

    this.rotation.x = 0;
    this.rotation.y = Math.PI / 2;
    this.rotation.z = 0;

};

THREE.CombinedCamera.prototype.toTopView = function() {

    this.rotation.x = - Math.PI / 2;
    this.rotation.y = 0;
    this.rotation.z = 0;

};

THREE.CombinedCamera.prototype.toBottomView = function() {

    this.rotation.x = Math.PI / 2;
    this.rotation.y = 0;
    this.rotation.z = 0;

};
